The present disclosure relates to a toner conveying device to convey a toner (developer), an image forming apparatus including the toner conveying device, and a toner case installed in the toner conveying device.
Electrophotographic image forming apparatus includes a toner conveying device for the purpose of supplying the toner to the surface of an image carrier (such as a photosensitive drum) and collecting the toner (hereinafter referred to as “waste toner”) remaining on the surface of the image carrier. For example, the toner conveying device includes a toner containing part configured to contain the toner and a conveying member configured to rotate around a rotation axis so as to convey the toner in the toner containing part. For example, the conveying member includes a screw shaft extending in directions of the rotation axis and a spiral fin installed around the screw shaft. The fin presses the toner accompanying to a rotation of the conveying member, thereby moving the toner.
In the toner conveying device configured as described above, the toner that has been charged may attach to the conveying member. As a result, a toner conveying space in the toner containing part may be reduced, thereby hindering toner conveying performance. Such a phenomenon is particularly conspicuous when the conveying member is made of a resin and more likely to occur when the toner with poor fluidity, such as the waste toner, is used.
In order to reduce attachment of toner to the conveying member as described above, there is a configuration that a portion of an agitating paddle is brought into contact with the conveying member, thereby supplying vibration to the conveying member. There is also a configuration that a twisted coil spring for vibration is attached to the conveying member. There is also a configuration that a projection provided at the toner containing part or an elastic member made of a film is brought into contact with the conveying member.
However, when the vibration is supplied to the conveying member in the configurations described above, force is applied to the conveying member in a direction (radial direction) perpendicular to the directions of the rotation axis. For that reason, the conveying member may be elastically deformed and then may be deflected, so that a portion of the conveying member may come into contact with the toner containing part, thereby causing noise. Further, when adopting the configuration in which the projection or the elastic member is brought into contact with the conveying member, noise may be caused at pitches corresponding to the number of the rotations of the conveying member rotating at high speed.